Circuit breaker



P E. MACK CIRCUIT BREAKER July 2; 1935.

Filed July 13, 1933 2 Sheets-Sheet l Mm Fa /Ty E Mazk P. E. MACK CIRCUITBREAKER July 2, 1935.

Filed July 13, 1955 2 Sheets-Sheet 2 "a 'IIIII/I; 'IIIII/IIIIIIIII zs umFEW-y E jf'ak Patented July 2, 1935 .1

UNITED STATES PATENT OFFICE CIRCUIT BREAKER Application July 13, 1933,Serial No. 680,209

7 Claims.

This invention relates to improvements in circuit breakers for use inignition systems of internal combustion engines and refers moreparticularly to a magneto circuit breaker for use in conjunction withsmall gasoline engines.

Heretofore, in magneto circuit breakers of this general type, themovable breaker point was carried by a pivotally mounted lever held inits closed contact making position by a tension spring. Thisconstruction was objectionable as at high speeds the lever arm began toflutter or chatter. Also the spring was very apt to break or elongatethe holes into which its ends were hooked.

This invention has as a general object the provision of a circuitbreaker particularly adapted to small gasoline engines, in which theaforementioned objectionable features are entirely overcome.

It is also an object of this invention to simplify the construction ofcircuit breakers and eliminate wearing connections by mounting themovable breaker point on the free end of a spring blade, the resiliencyof which holds the contacts closed.

It is a further object of this invention to provide means operating inoil for actuating the circuit breaker.

In this connection, it is a feature of this invention to provide novelmeans for conducting oil to the cam follower which actuates the circuitbreaker and for draining excess oil therefrom.

With the above and other objects in view which will appear as thedescription proceeds, my invention resides in the novel construction,combination and arrangement of parts substantially as hereinafterdescribed and more particularly defined by the appended claims, it beingunderstood that such changes in the precise embodiment of the hereindisclosed invention may be made as come within the scope of the claims.

In the accompanying drawings, I have illustrated one complete example ofthe physical embodiment of my invention constructed according to thebest mode I have so far devised for the practical application of theprinciples thereof, and in which:

Figure 1 is a section view through one end of the crank shaft of aconventional gasoline en gine illustrating part of the magneto assemblyand the application of this invention thereto;

Figure 2 is a section view through one bearing for the crank shaft, saidview being takenon the plane of the line 22 in Figure 1;

Figure 3 is a detail section view through Figure 2 on the plane of theline 33; and

Figure 4 is a perspective view of the bearing bushing showing the oildrain for the cam follower.

Referring now more particularly to the accompanying drawings, thenumeral l represents the crank shaft of an internal combustion engine,one end of which is journalled in a bearing 2 carried by a stationaryhub 3. The hub 3 forms one wall of the crank case and provides supportfor a magneto assembly indicated generally by the numeral 4. Thisassembly comprises an armature coil 5 wound on a laminated metalU-shaped frame S as is customary. Inasmuch as the specific constructionof the magneto assembly forms no part of this invention, it has not beenshown in detail and further description thereof is unnecessary.

The outer extremity of the crank shaft end shown mounts a fiy-wheel l,which overlies the magneto assembly. a

The bearing 2 is lined with a bushing 8 having an oil inlet opening 9which aligns with an oil passage ID in the top portion of the bearinginner end. As best shown in Figure 3 the inner wall of the hub 3 abovethe bearing has two inclined ribs H, which define a pocket or recess inwhich oil splashed upwardly by the revolving crank collects to flowthrough the passage l0 and the opening 9 into the bushing. The outer endof the bushing communicates with a drain passage l2, which leads back tothe crank case, there being an automatic valve l3 in said passage.

The circuit breaker per se comprises a; stationary contact l4 adjustablymounted on the bearing 2 to be engaged by a movable contactor l5 mountedon the free end of a spring blade 15. The blade I6 is anchored to ablock I l of insulating material secured by screws I8 to the adjacentwall of the hub 3, the spring blade l6 being secured to the block by abolt l9. The blade is held against turning about the bolt by flanges 20formed on the block and projecting down over the side edges of theblade.

The extreme end of the blade opposite the contactor projects beyond theblock I! to provide a terminal to which a conductor wire 2| is attachedto connect the same in the electrical circuit in the customary manner.

The undersurface of the block I! against which the spring blade [6engages is curved away from the blade from a point approximately in linewith the bolt l9 to aiford a support against which the bladeprogressively rests as it is flexed during movement to open position.Such movement of the blade is efiected by a push pin or cam follower 22formed of insulating material and slidable in a radial bore 23 in thebearing 2 with its inner end aligned with a flat spot 24 forming a camon the shaft. Obviously, upon each revolution of the shaft, and

the consequent alignment of the flat spot 24 with the push pin, thebreaker points are permitted to contact.

Theflprogressive engagement of the blade IS with the curved surface ofthe supporting block causes the fulcrum point to move outwardly alongthe support and consequently, shortens the free end portion of thespring. This chang ing of the effective length of the spring alters itsperiod of vibration and effectively quenches all harmonic vibrationsthat tend to cause chattering at the contact points. Overstraining ofthe spring blade is also prevented by this construction.

A rebound guard 25, which consists of a strip of stiff metal is fixed tothe support over the spring blade and extends a substantial distance outover the free end portion of the spring to limit outward swinging of thespring and cooperate With the supporting block 1 to prevent chattering.I V

It will be noted that the inner end of the push pin or cam followerpasses through an opening 26 in the bushing sleeve 8. This opening,which obviously aligns with the radial bore 19 in the bearing, issufiiciently large to permit oil to flow up into the bore i9.conseqently floats? in oil'. 7 To preclude the pumping of oil outthrough the radial bore 49 by the push pin i8, a diagonal drain slot, 2?leads from the hole 26 to the adjacent drained end of the bushing, thecapacity of the slot'being such that only the excess oil is carried awayfrornthe push pin. a

From the foregoing description taken inconnection with; the accompanyingdrawings it will be 1 eadily apparent to those skilled in the art, thatthis invention materially simplifies the construction of magneto circuitbreakers and eliminates wear from all active parts of its assembly. t isalso apparent that by this construction, objectionable chattering andheretofore unsatisfactory operation at high speeds is entirely overcome.

What I claim as my invention is:

l. A circuit breaker comprising a stationary contact, a movablecontactor engageable therewith, a spring blade carrying the movablecontactor, means mounting the spring blade comprising a support to whichthe spring blade is attached with one flat side of the spring blade inengagement with one surface of the support, and means to flex the springblade toward the support to disengage the contactor from the contact,the surface of the support with which the spring engages being curved.so as to automatically shift the fulcrum about which the blade bendsoutwardly along the blade to shorten its eifective'length as the springblade is flexed. V

2. In a circuit breaker, a pair of separable contacts, a spring blademounting one of the contacts, a support to which one end portion of thespring blade is secured, said support having a portion provided with. acurved wall with which the spring blade engages progressively at greaterdistancesfrom its point of attachment to the support upon flexing of theblade toward the support, and means to flex the blade 3. In a circuitbreaker of the character described, a pair of contacts, a springbladecarryme, one of thecontacts, a supporting block for The push pinthe spring blade, means to attach the spring blade to the supportingblock so that the resiliency of the spring blade holds its contact inengagement with the other contact, said supporting block having aportion projecting from the point of attachment of the blade theretotoward the free end of the spring blade with which the blade isprogressively engaged as it is flexed to disengage its contact from theother contact, and means to periodically flex the blade toward thesupport;

4; In a circuit breaker of the character described, a fixed contact, anda movable contactor engageable therewith, a spring blade carrying themovable contactor at one end portion, a

supporting member for the blade having a the spring bladehaving a curvedsurface, means to attach the spring blade to; the supporting member at adistance from'the contactor with the curved surface of the supportingmember disposed between said attaching means and the fixed contact sothat upon outward flexing of the spring blade to disengage the contactorfrom the contact the curved surface is progressively engaged by thespring blade, means to periodicallyflex the spring blade to disengagethe con tactor from the contact, and a member overlying the mounted endportion of the spring blade to provide a rebound guard and cooperatewith the curved surface of the supporting member to preclude chatteringbetween the contactor and the contact.

6. In a circuit breaker o f the character described, a stationary memberhaving a shaft bearing and a wall substantially perpendicular to theaxis of the bearing, a fixed contact carried by the bearing, a movablecontactor, a spring arm carrying the movable contactor, a supportingblock mounted on said Well, means to attach the spring arm to saidsupporting block at a distan'ce-from the movable contactor, saidsupporting blockv having a surface with which the spring armprogressively engages as it is flexed to disengage the movable contactorfrom the fixed contact, a push pin mounted in a radial bore in thebearing, and a shaft mounted to turn in said bearing and having means toperiodically actuate the push pinto flex the spring arm andperiodically, disengage the movable'contactor from the fixed contact,

7. In a relay, a movable mem'b'enia resilient element arranged to biassaid member, and a cam mounted in contact with said resilient element,said cam having a contour departing slightly from that of said resilientelement and being arranged to change the effective free length of saidresilient element upon movement .of said member.

' PERRY E. MACK.

